scholarly journals An Effect of Tip Clearance on Aero Performance in Axial Flow Compressors for Aero Gas Turbine Engines

2019 ◽  
Vol 9 (4) ◽  
pp. 769-776
Author(s):  
Manjunath S. Dalbanjan et al., Manjunath S. Dalbanjan et al., ◽  
Keyword(s):  
Gas Turbine ◽  
Axial Flow ◽  
Tip Clearance ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Axial Flow Compressors

Improved criteria for stall-free preliminary design of axial compressor of aero gas turbine engines

2018 ◽  
Vol 233 (9) ◽  
pp. 3286-3297 ◽  
Author(s):  
MR Aligoodarz ◽  
A Mehrpanahi ◽  
M Moshtaghzadeh ◽  
A Hashiehbaf
Keyword(s):  
Gas Turbine ◽  
Large Scale ◽  
Axial Compressor ◽  
Axial Flow ◽  
Design Criterion ◽  
Flow Coefficient ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Parameter Ranges ◽  
Axial Flow Compressors

A worldwide effort has been devoted to developing highly efficient and reliable gas turbine engines. There exist many prominent factors in the development of these engines. One of the most important features of the optimal design of axial flow compressors is satisfying the allowable range for various parameters such as flow coefficient, stage loading, the degree of reaction, De-Haller number, etc. But, there are some applicable cases that the mentioned criteria are exceeded. One of the most famous parameters is De-Haller number, which according to literature data should not be kept less than 0.72 in any stage of the axial compressor. A deep insight into the current small- or large-scale axial flow compressors shows that a discrepancy will occur among design criterion for De-Haller number and experimental measurements in which the De-Haller number is less than the design limit but no stall or surge is observed. In this paper, an improved formulation is derived based on one-dimensional modeling for predicting the stall-free design parameter ranges especially stage loading, flow coefficient, etc. for various combinations. It was found that the current criterion is much more accurate than the De-Haller criterion for design purposes.

A Mean Line Prediction Method for Axial Flow Turbine Efficiency

1982 ◽  
Vol 104 (1) ◽  
pp. 111-119 ◽  
Author(s):  
S. C. Kacker ◽  
U. Okapuu
Keyword(s):  
Gas Turbine ◽  
Axial Flow ◽  
Prediction Method ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Loss System ◽  
Turbine Efficiency ◽  
Wide Range ◽  
Line Loss ◽  
Axial Turbines

A mean line loss system is described, capable of predicting the design point efficiencies of current axial turbines of gas turbine engines. This loss system is a development of the Ainley/Mathieson technique of 1951. The prediction method is tested against the “Smith’s chart” and against the known efficiencies of 33 turbines of recent design. It is shown to be able to predict the efficiencies of a wide range of axial turbines of conventional stage loadings to within ± 1 1/2 percent.

scholarly journals Microwave Blade Tip Clearance Measurement System

1996 ◽  
Author(s):  
Richard Grzybowski ◽  
George Foyt ◽  
Hartwig Knoell ◽  
William Atkinson ◽  
Josef Wenger
Keyword(s):  
Gas Turbine ◽  
Measurement System ◽  
Ceramic Materials ◽  
Tip Clearance ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Phase Measurements ◽  
Blade Tip ◽  
Clearance Control ◽  
Blade Tip Clearance

This paper describes the development of a Microwave Tip Clearance Measurement System for use in the gas turbine environment Applications for this sensor include basic tip clearance measurements, seal wear measurement and active blade tip clearance control in gas turbine engines. The system being developed was designed for useful operation to temperatures exceeding 1093°F, since only ceramic materials are directly exposed in the gas path. Other advantages of this microwave approach to blade tip clearance sensing include the existence of an inherent self-calibration in the sensor that permits accurate operation despite temperature variations and possible abrasion by the rotating blades. Earlier experiments designed to simulate this abrasion of the sensor head indicated that rubs as deep as 1 mm (40 mils) were easily tolerated. In addition, unlike methods based upon phase measurements, this method is very insensitive to cable vibration and length variations. Finally, this microwave technique is expected to be insensitive to fuel and other engine contamination, since it is based on the measurement of resonant frequencies, which are only slightly affected by moderate values of loss due to contamination.

scholarly journals A review of blade tip clearance–measuring technologies for gas turbine engines

2020 ◽  
Vol 53 (3-4) ◽  
pp. 339-357 ◽  
Author(s):  
Bing Yu ◽  
Hongwei Ke ◽  
Enyu Shen ◽  
Tianhong Zhang
Keyword(s):  
Gas Turbine ◽  
Measuring Method ◽  
Gas Turbine Engine ◽  
Tip Clearance ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Turbine Engine ◽  
Blade Tip ◽  
Safety And Stability ◽  
Blade Tip Clearance

Blade tip clearance is one of the important parameters affecting the performance, safety and stability of a gas turbine engine. However, it is difficult to measure the tip clearance in real time and accurately during the development and test process of an engine. In order to promote the development of tip clearance–measuring technology and the optimal design of the gas turbine engine, some typical measuring methods of tip clearance and a novel measuring method based on AC discharge are introduced. In this article, the significance for measuring tip clearance of an engine is illustrated first. Then, operating principles, characteristics and developments of those typical measurement approaches are introduced. After that, these methods are analyzed, and the particular characteristic of each measuring approach is summarized.

scholarly journals Laser-Optical Blade Tip Clearance Measurement System

1981 ◽  
Vol 103 (2) ◽  
pp. 457-460 ◽  
Author(s):  
J. P. Barranger ◽  
M. J. Ford
Keyword(s):  
Gas Turbine ◽  
Measurement System ◽  
Optical Measurement ◽  
Tip Clearance ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Turbine Engine ◽  
Blade Tip ◽  
Graphic Terminal ◽  
Blade Tip Clearance

The need for blade tip clearance instrumentation has been intensified recently by advances in technology of gas turbine engines. A new laser-optical measurement system has been developed to measure single blade tip clearances and average blade tip clearances between a rotor and its gas path seal in rotating component rigs and complete engines. The system is applicable to fan, compressor and turbine blade tipe clearance measurements. The engine mounted probe is particularly suitable for operation in the extreme turbine environment. The measurement system consists of an optical subsystem, an electronic subsystem and a computing and graphic terminal. Bench tests and environmental tests were conducted to confirm operation at temperatures, pressures, and vibration levels typically encountered in an operating gas turbine engine.

Observed Rotordynamic Phenomena in Aircraft Gas Turbine Development

2015 ◽  
Author(s):  
Fredric F. Ehrich
Keyword(s):  
Gas Turbine ◽  
High Speed ◽  
Nonlinear Effects ◽  
Aircraft Engine ◽  
Tip Clearance ◽  
Resonant Peak ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Nonlinear Responses ◽  
Remedial Actions

Observations, analysis and understanding of out-of-the-ordinary rotordynamic phenomena (including several instabilities and nonlinear responses) observed in aircraft gas turbine engines and other high-speed rotating machinery over the course of the author’s career in the design and development of aircraft gas turbine engines are described. Some observed phenomena were already widely recognized in the rotordynamic community such as: • Hysteretic whirl • The tip clearance effect on stability of turbomachinery rotors • Instability due to trapped liquids in the rotor • Hysteresis in the resonant peak amplitude • Effective suppression of rotor instability by anisotropy in the engine support structure Other observations were fairly new to the field of rotordynamics at that time they were observed but were identified as being new manifestations of vibration phenomena already familiar to vibration technologists in fields other than high-speed rotordynamics such as: • Sum-and-difference frequency response • Relaxation oscillations • Nonlinear effects of anisotropic clearance in roller and gas bearings At that time these phenomena were observed, the pressure for remediation of the problems they represented in the context of ongoing aircraft engine development resulted in intense attention and analysis which, in turn, often resulted in new insights, useful diagnoses, and effective remedial actions.

Tip Clearance Control Concept in Gas Turbine H.P. Compressors

2012 ◽  
Author(s):  
G. I. Ekong ◽  
C. A. Long ◽  
P. R. N. Childs
Keyword(s):  
Gas Turbine ◽  
Tip Clearance ◽  
Test Facility ◽  
Turbine Engines ◽  
Thermodynamic Efficiency ◽  
Gas Turbine Engines ◽  
Critical Importance ◽  
Operating Cycle ◽  
Expansion Time ◽  
Clearance Control

To improve the thermodynamic efficiency of aircraft engine and other gas turbine engines, higher and higher pressure ratios are desired in conjunction with more refined engine cycles. In the high pressure compressor, higher pressure ratios result in lower aspect blades and enhanced sensitivity of the engine design to radial clearance effects. The tip clearance in the axial flow compressor of modern commercial civil aero-engines is of critical importance in terms of both mechanical integrity and performance. Typically as the clearance between the compressor blade tips and the casing increases, the aerodynamic efficiency will decrease and therefore the specific fuel consumption and operating costs will increase, and the clearance is therefore of critical importance to civil airline operators and their customers alike. A design exercise was performed and a series of conceptual solutions were developed using the theory of inventive problem solving (TRIZ) process and their potential viability in clearance control was investigated with thermal modelling. TRIZ was selected as an appropriate tool as the issue was long-standing having been the focus of previous projects, and robust design solutions were being sought. In order to validate the concepts, use was made of a test facility developed at the University of Sussex, incorporating a rotor and an inner shaft scaled down from a Rolls Royce Trent aeroengine to a ratio of 0.7:1. The mechanical design of the test facility allows the simulation of flow conditions in the HP compressor cavity equivalent to the Trent 1000 aero-engine, with a rotational speed of up to 10000 rpm. The idle and maximum take-off conditions in the square cycle correspond to in-cavity rotational Reynolds numbers of 3.1×106 ≤ Reφ ≤ 1.0×107. The finite element thermomechanical model has been built to validate the engine measurements. This paper describes the use of TRIZ and the development of a selected concept and the detailed evaluation for reduction and control of tip clearance in HP compressors. This was achieved through the reduction in the compressor disc heat expansion time constant by improving drum heat transfer using bleed air from the compressor core flow. This paper explores the trade-offs between clearance and efficiency and develops and explores concepts to control the compressor tip clearance throughout the engine operating cycle. The project involved modelling of potential solutions and use of experimental facilities, a rotating compressor cavity rig, in order to explore the physical principles and demonstrate proof of concept for controlling tip clearance in HP compressors of gas turbine engines.

Optimisation Method for Multistage Compressors

2021 ◽  
pp. 38-59
Author(s):  
E.S. Goryachkin ◽  
V.N. Matveev ◽  
G.M. Popov ◽  
O.V. Baturin ◽  
Yu.D. Novikova
Keyword(s):  
Gas Turbine ◽  
Cfd Simulation ◽  
Pressure Ratio ◽  
Axial Flow ◽  
Stability Margin ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Data Vector ◽  
Minimum Number ◽  
Multistage Compressors

The paper presents an algorithm for seeking an optimal blade configuration for multistage axial-flow compressors. The primary tool behind the algorithm is 3D CFD simulation, augmented by commercial optimisation software. The core of the algorithm involves feeding an initial data vector to the parametric simulation module so as to form a "new" blade geometry, which is then transferred to 3D computational software. The results obtained are further processed in a program that implements the algorithm for seeking the optimum and forms a new input data vector to achieve the set goal. We present a method of parametrically simulation the blade shape, implemented in a software package, making it possible to describe the shape of the compressor blade profiles using a minimum number of variables and to automatically change the shape in the optimisation cycle. The algorithm developed allows the main parameters of compressor operation (efficiency, pressure ratio, air flow rate, etc.) to be improved by correcting the profile shape and relative position of the blades. The algorithm takes into account various possible constraints. We used the method developed to solve practical problems of optimising multistage axial compressors of gas turbine engines for various purposes, with the number of compressor stages ranging from 3 to 15. As a result, the efficiency, pressure ratio and stability margin of gas turbine engines were increased

Thermal Tip Clearance Control for Centrifugal Compressor of an APU Engine

1994 ◽  
Vol 116 (4) ◽  
pp. 629-634 ◽  
Author(s):  
G. Eisenlohr ◽  
H. Chladek
Keyword(s):  
Gas Turbine ◽  
Centrifugal Compressor ◽  
Operating Conditions ◽  
Tip Clearance ◽  
Qualitative Description ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Turbine Engine ◽  
Design Calculations ◽  
Clearance Control

To master today’s demand for efficiency and compactness of centrifugal compressor components for small gas turbine engines the main attention must not only be given to the aerodynamic design of the impeller and diffuser components, but also to the installation situation of the surrounding parts. A vital aspect is the tip clearance control between impeller and shroud casing over the total operating range. Using the radial compressor for a small gas turbine engine, developed at BMW Rolls-Royce, the importance of tip clearance control is demonstrated. The possibilities for influencing and optimizing passive tip clearance control by design features are described; transient expansion processes must be considered when using a thermal tip clearance control. The results of the design calculations are compared with the results on the test stand and the engine itself. An effort is made to find a qualitative influence of tip clearance to the engine power output at operating conditions. This qualitative description is substantiated by test results with different tip clearances at the compressor teststand.

Sign in / Sign up

Export Citation Format

Share Document